The present invention is directed to a microprocessor based system for use in a vehicle for controlling the operation of various auxiliary devices, such as wheelchair lifts, lift gates, personal lifts, or any other device that requires activation with the vehicle in a secure position.
In the last several years, we have witnessed the increased use of various auxiliary lift devices, such as wheelchair lifts, lift gates and personal lifts, which are used to allow persons with disabilities or other infirmities to more easily enter and exit vehicles (such as buses, vans and sport utility vehicles (SUV""s)). As can be appreciated, when such devices are used, it is important that the vehicle be prevented from moving during the operation of the auxiliary device, insofar as movement of the vehicle can result in injury to the user. Consequently, the American Disabilities Act (ADA), Title 49, Code of Regulations has implemented various lift interlock requirements to ensure that vehicles will not operate when lift devices are employed.
U.S. Pat. No. 4,420,286, issued to Hanson et al., and U.S. Pat. No. 5,052,879, issued to Wolfe et al., acknowledge that an interlock device used in conjunction with a wheelchair lift, or an invalid lift, must or should be used. For example, Hanson et al. describes an invalid lift apparatus including an interlock switch 186. According to Hanson et al., after the driver brings the vehicle to a stop, the gear shift lever must be placed in the xe2x80x9cparkxe2x80x9d position to close the interlock switch 186, for the invalid lift apparatus to operate.
This patent, however, does not address the use of a parking brake or lift door input as parameters which are also helpful in ensuring that the vehicle will not operate while the lift apparatus is being used. In this respect, the Hanson et al. invention does not lock the vehicle into xe2x80x9cparkxe2x80x9d when the lift door is open, nor when the parking brake is applied, nor does it incorporate system diagnostics and diagnostic displays.
The Wolfe et al. patent is directed to a wheelchair lift and transfer system, and references a xe2x80x9cparkxe2x80x9d cutoff switch 4 (in FIG. 18). The Wolfe et al. system also does not lock the vehicle in xe2x80x9cparkxe2x80x9d when the lift door is open, or when the parking brake is employed, nor does the system incorporate system diagnostics and diagnostic displays.
The deficiencies of the prior art are addressed by the present invention which is directed to an intelligent lift interlock system used to prevent a vehicle from being moved when a auxiliary device is operated. The auxiliary device used in the present system may include a wheelchair lift, a lift gate, a personal lift, or any other device that requires activation with the vehicle in a secure position. The present invention preferably provides the option of activating or deactivating an auxiliary device only when the vehicle is in park. For instance, the system can be adapted so that an electrically controlled front door can only be activated when the vehicle is in park.
The present invention preferably includes a microprocessor controller for operating the auxiliary device based on transmitting the status of various sensors to the microprocessor. The lift interlock system, including the microprocessor, can be installed in the vehicle as original equipment or can be added at a later time. In this respect, the present invention is preferably designed to use sensors that are already on the vehicle by connecting them to OEM connectors for an easy xe2x80x9cplug and playxe2x80x9d installation. No cutting of OEM harnesses would be required. The present invention also preferably includes a module having diagnostic display and diagnostic capabilities, as well as a dedicated park output which can drive a relay, lamp, buzzer, or any other external device when the vehicle is in park.
Since the present invention is designed to prevent or reduce injuries associated with allowing various people with disabilities and/or infirmities to exit or enter the vehicle, the auxiliary device should only operate when all of the following conditions are met: 1) the vehicle is in park; 2) the parking brake is applied; 3) the vehicle""s ignition is on; 4) the lift power switch is engaged; and 5) the lift door is open. Although the microprocessor utilized in the present invention can allow the operation of the lift device to be activated when one or fewer than all of the above noted conditions are met, for safety reasons, the vehicle lift is preferably operated only when all of these conditions are met. Additionally, the present invention is preferably designed to prevent the vehicle from being shifted out of xe2x80x9cparkxe2x80x9d if the lift door is open, or when the parking brake is applied.
Furthermore, the present invention preferably operates to prevent the vehicle from being shifted out of xe2x80x9cparkxe2x80x9d anytime the parking brake is applied. This feature will eliminate excessive parking brake wear which can occur if the parking brake is inadvertently engaged while driving.